Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752433Ab3FZJEG (ORCPT ); Wed, 26 Jun 2013 05:04:06 -0400 Received: from b.ns.miles-group.at ([95.130.255.144]:1661 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751916Ab3FZJEE (ORCPT ); Wed, 26 Jun 2013 05:04:04 -0400 Message-ID: <51CAAE7C.9090003@nod.at> Date: Wed, 26 Jun 2013 11:03:56 +0200 From: Richard Weinberger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130510 Thunderbird/17.0.6 MIME-Version: 1.0 To: Chen Gang CC: Jeff Dike , Arnd Bergmann , dhsharp@google.com, Mark Brown , "sfr@canb.auug.org.au" , Steven Rostedt , Ingo Molnar , uml-devel , uml-user , "linux-kernel@vger.kernel.org" , Linux-Arch Subject: Re: [PATCH] include/asm-generic/io.h: add 'UML' case just like 'no-MMU' References: <51CA8AB8.7080504@asianux.com> <51CA900E.9020407@nod.at> <51CA9E92.4000107@asianux.com> <51CAA0C6.60007@nod.at> <51CAA78C.5040900@asianux.com> <51CAA8D6.9000505@nod.at> <51CAAD1D.8050801@asianux.com> In-Reply-To: <51CAAD1D.8050801@asianux.com> X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1789 Lines: 43 Am 26.06.2013 10:58, schrieb Chen Gang: > On 06/26/2013 04:39 PM, Richard Weinberger wrote: >>>>>>>>>> The drivers internal code has already check the related return value, >>>>>>>>>> so it is the architecture's duty to 'tell' the driver whether support >>>>>>>>>> io memory (e.g. define ioremap, but return NULL). >>>>>> It does so already by setting CONFIG_HAS_IOMEM=n >>>> >>>> Excuse me, I use "grep -rn ioremap *" under "include/" and "arch/um/" >>>> directory, but can not find the related definition for 'ioremap'. >>>> >>>> Is there another declaration or definition way which I don't know ? >>>> (maybe it is). >> Both UML and s390 (in the !CONFIG_PCI) do not define ioremap() because >> without io memory you cannot have a ioremap(). >> > > I assume if ioremap() return NULL, it means "without io memory", is it > correct ? > > If it is correct, "define a dummy ioremap(), and return NULL" is just > the meaning that you mentioned above. > > If so, for UML, it is not requirement, but recommend to define a dummy > ioremap() which return NULL, so can be generic enough to mach all cases. No. Not setting CONFIG_HAS_IOMEM=y means "This arch has no io memory and therefore no functions to mess with it". Let's get back to the real problem, drivers/ptp/ptp_pch.c does not build on UML (and I'm very sure also not on S390). Fix the issue by making it depend on HAS_IOMEM. Btw: Did you actually look at this driver? There is *zero* reason to have it on UML. ...like 99.9% of all other drivers which use io memory. Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/